Tensioning system



1953 R. BARREDO DE VALENZUELA TENSIONING SYSTEM 3 Sheets-Sheet 1 Filed Oct. 14. 1953 INVENTOR. lzlmeao GAMEzw V! VALill/Zl/[LA Jan. 21, 1958 R. BARREDO DE VALENZUELA 2,

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Jan. 21, 1958 R. BARREDO DE VALENZUELA 2,820,606

TENSIONING SYSTEM 3 Sheets-Sheet 3 Filed Oct. 14. 1953 United States Patent TENSIONING SYSTEM Ricardo Barredo de Valenzuela, Madrid, Spain Application October 14, 1953, Serial No. 386,088

Claims priority, application Spain October 15, 1952 8 Claims. (Cl. 254-29) The invention relates to an apparatus for tensioning the rods or wires of reinforced concrete.

It is an object of the invention to provide improved means for obtaining uniform tensioning of reinforcements for concrete structures.

The features which I desire to protect herein are pointed out with particularity in the appended claims. The invention itself, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view showing certain parts of a device according to the invention for performing a first tensioning step;

Fig. 2 is a sectional view taken through the vertical axis of the device of Fig. 1,

Fig. 3 is a vertical sectional view of the apparatus showing partly in section along line C-D of Fig. 4 and partly in plan view, the parts performing the final tensioning step.

Fig. 4 is a cross section taken on line AB of Fig. 3.

According to the invention, the steel wires employed as reinforcement for the cement are tensioned in groups of three which pass through the same slot and are anchored simultaneously by means of the same wedge; in this way, the pressure exerted by the device is the same for each wire.

A preliminary tension is applied to each wire by a small appliance, which will be described below, whereby the wires are temporarily anchored, one after the other, in another member from which they are then drawn in order to tension each group of three wires; each of said groups of three wires is secured to the tensioning device proper; this device comprises a supporting point which lies in a plane in the center of the triangle formed by the three wire groups to be tensioned and forms a tetrahedron supported in one vertex while the three groups of three wires are suspended at the three vertices opposite said vertex. This arrangement causes the tensions to be in equilibrium because otherwise the wires would turn around the vertex to effect correction.

Referring now to the drawings, the reference letter a designates the wires to be tensioned; b is a member which is a part of the tensioning device and receives, one after the other, the wires a, which are secured by the provisional wedges d.

A plate 1 serves to place the members 12 into position and to withdraw the same; is a small auxiliary machine in the form of a racket grip which produces the preliminary tension.

It will be noted from the drawing that three members b are necessary for each group of nine wires; the three other circles correspond to three other openings which serve for mounting the tensioning device. The center opening is provided for the passage of the point of support; e is the anchor plate, which may be secured to the forming.

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In the Figures 3 and 4 illustrating the second tensioning stage, there are shown:

(1) The anchor plate e;

(2) The three wires of a group engaged or anchored by the wedge g;

(3) A member b which receives three other wires and is secured to the plate 1 by means of a nut i; and a stem h, which is screwed into the wedge g and facilitates the placing of the three members b;

(4) A threaded bolt 1:, which with its nut allows to draw back the plate f (there are three bolts k in the assembly);

(5) A gauge cell T, which serves as a central support for the assemblage and which measures, with the micrometer M, the tension of the wires by the deformation of the cell.

Said tension and said measurement may also be obtained by means of a hydraulic jack and a manometer, or by any other suitable means.

When the bolts k are made tubular, they may also be anchored directly on the members b; in this case, the plates 1 can be omitted or used only as guide means for positioning the members b.

While I have described my invention in connection with particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without departing from the invention. I therefore aim in the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

1 claim:

1. A tensioning system for a two-stage tensioning of reinforcements of concrete structures comprising an anchor plate, three openings in said plate for the passage of three groups of reinforcing wires, said openings forming the vertices of an equilateral triangle, a wedge in each of said openings anchoring simultaneously all the wires of the respective group, individual wedges anchoring temporarily each of said wires for preliminary tensioning, means for imparting to each of said wires a preliminary tension, guides cooperating with said individual wedges during said preliminary tensioning, and final tensioning means supported in the axis of said equilateral triangle.

2. A tensioning system for a two-stage tensioning of reinforcements of concrete structures comprising an anchor plate, an upper plate spaced from and parallel to said anchor plate, three openings in said anchor plate for the passage of three groups of reinforcing wires, said openings forming the vertices of an equilateral triangle, a main wedge in each of said openings anchoring simultaneously all the wires of the respective group, individual wedges anchoring temporarily each of said wires for preliminary tensioning, means imparting to each of said wires individually a preliminary tension, removable guide sleeves secured in said upper plate coacting with said individual wedges, final tensioning means for said three groups of wires mounted on said upper plate and supported on said anchor plate, the supporting point on said anchor plate and the supports for the three groups of Wires to be tensioned forming a tetrahedron, which tetrahedron ensures equalization of the tensions by allowing the groups of wires to turn on said supporting point for correcting unequal tensioning.

3. A tensioning system as defined in claim 2, comprising shafts screwed on said main wedges and coacting with said individual wedges.

4. A tensioning system as defined in claim 2, comprising a gauge cell serving as central support for the device and a micrometer responsive to the deformation of said cell for measuring the tension of the wires.

5. A tensioning system as defined in claim 2, comprisingv a hydraulic jack serving as final tensioning means and central support. V

6. A tensioning system as defined in claim 2, comprising screw bolts connecting said upper plate andfinal -tensioning means.

7. A tensioning system for a two-stage tensioning of reinforcements of concrete structures, comprising an anchor plate, three openings in said anchor plate for the passage of three groups of reinforcing wires, said openings vforming the vertices of an equilateral triangle, a mainwedge in each of said openings anchoring simultaneously all the Wires of the respective group, individual wedges anchoring temporarily each of said wires for preliminary tensioning, means imparting a preliminary tension individually toeach of said wires, a guide sleeve for each of, said three groups of wires coacting with said individual wedges, final tensioning means for said three groups of wires supported on said anchoring plate in the center of said equilateral triangle, and means holding each of said guiding sleeves in position.

8. A tensioning system for a two-stage tensioning .of reinforcements of concrete structures, comprising three spaced wire holding means located in the same plane and forming the vertices of an equilateral triangle, and tensioning means supporting said holding means, the supporting point of said tensioning means forming the vertex of a tetrahedron of which'the other vertices are defined by said vertices of the: triangle.

References Cited in the file ofthispatent UNITED STATES PATENTS 1,186,554 Crisenberry June 13, 1916 2,511,761 Barber et; a1. June 13, 1950 2,637,895 Blaton May 12, 1953 FOREIGN PATENTS 578,768 Germany June 16,. 1933 543,249 Great Britain -5. V Feb. 16,1942

692,354 Great Britain June 3,1953 

